Crater Lake National Park

Location: Oregon

Year Established: 1902

Area: 183,224.05 acres (741.5 km2)

Annual Visitors: 535,508

Crater Lake lies in the caldera of an ancient volcano called Mount Mazama that collapsed 7,700 years ago. It is the deepest lake in the United States and is famous for its vivid blue color and water clarity. There are two more recent volcanic islands in the lake, and, with no inlets or outlets, all water comes through precipitation.